Messages in this thread Patch in this message | | | Subject | [PATCH] Fix possible race with 4level-fixup.h | From | Benjamin Herrenschmidt <> | Date | Thu, 17 Feb 2005 18:19:07 +1100 |
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Hi !
When using 4level-fixup.h, a PMD page may end up beeing freed before the matching PGD entry is cleared due to the way the compatibility macros work. This can cause nasty races on some architectures.
This patch fixes it by defining pud_clear() to be pgd_clear(). That means we'll actually write 0 twice, a small price to pay here, especially seeing how easy it is to convert to the new headers anyway (hint hint, ppc & ppc64 patches as soon as 2.6.11 is out).
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Index: linux-work/include/asm-generic/4level-fixup.h =================================================================== --- linux-work.orig/include/asm-generic/4level-fixup.h 2005-01-24 17:09:49.000000000 +1100 +++ linux-work/include/asm-generic/4level-fixup.h 2005-02-17 18:10:38.000000000 +1100 @@ -24,7 +24,7 @@ #define pud_bad(pud) 0 #define pud_present(pud) 1 #define pud_ERROR(pud) do { } while (0) -#define pud_clear(pud) do { } while (0) +#define pud_clear(pud) pgd_clear((pgd_t *)(pud)) #undef pud_free_tlb #define pud_free_tlb(tlb, x) do { } while (0)
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